. Amphioxus and the ancestry of the vertebrates [microform]. Vertebrates; Chordata; Fishes; Ascidiacea; Vertébrés; Cordés; Poissons; Ascidiacés. LVTEKXAI. AAA T( >M 1'. 9« the ventral tube, so as to form a vesicular (lilatatu)u cov- ered over by a thin membrane. The rej^ion of the nerve- tube, over which this dorsal dilatation extends, has been compared by IIatscmek, who discovered it, to the iiiidit/ld vMoNi^ata of the craniate Vertebra whi(.h is similarly roofed in only by membrane. In the fijUv i^rown condi- tion, however, it seems to be largely obliterated by the ||#|iw. Fig. 46. â
. Amphioxus and the ancestry of the vertebrates [microform]. Vertebrates; Chordata; Fishes; Ascidiacea; Vertébrés; Cordés; Poissons; Ascidiacés. LVTEKXAI. AAA T( >M 1'. 9« the ventral tube, so as to form a vesicular (lilatatu)u cov- ered over by a thin membrane. The rej^ion of the nerve- tube, over which this dorsal dilatation extends, has been compared by IIatscmek, who discovered it, to the iiiidit/ld vMoNi^ata of the craniate Vertebra whi(.h is similarly roofed in only by membrane. In the fijUv i^rown condi- tion, however, it seems to be largely obliterated by the ||#|iw. Fig. 46. â'I'lanhViisf s( ction ihr(iiii;li tin- ^^ cord hefwecn the second ;inil tliird .sensory roots. (.Atti'r Kiilinr,.) .i,'.*'. l)orsal afijjri'ijation ot 'lls (extending between the seeoiid anci filth pairs of sensory nerves; a somewhat siniihir Kioiip of ijanghon-cells oeeiirs (Jii ventral side of nerve-cord below the central canal between the fourth and sixth sensory nerves.) </./â . Dorsal root. ,]);; fibres, cenirui ; in this case efjuaily w ide throughout its entire iicight, and so all along the spinal cord. sh. Sheath of nerve-cord. development of a mass of larj^e j,Mnglion-cells which tend backwards as far as the fifth pair of sensory nerves (Fit;-- 46). All there is of a brain in Amphioxus is shown in Fit;. 45. The cerebral vesicle is a plain cavity without any true subdivision into ; In the development of. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Willey, Arthur, 1867-1942. New York; London : Mcmillan
Size: 1875px × 1333px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectfishes, bookyear1894
